From 86a2a54640132ff18fbceaa18c0f1066b3dbb19d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Matthias=20Mail=C3=A4nder?= <matthias@mailaender.name>
Date: Sun, 22 Nov 2015 11:37:58 +0100
Subject: [PATCH 1/2] catch MappingExceptions in NatDevice.GetExternalIP

---
 OpenRA.Game/Network/UPnP.cs                    | 18 +++++++++++++++++-
 .../Widgets/Logic/Lobby/LobbyUtils.cs          |  4 ++--
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/OpenRA.Game/Network/UPnP.cs b/OpenRA.Game/Network/UPnP.cs
index e65679967b..29525a10f0 100644
--- a/OpenRA.Game/Network/UPnP.cs
+++ b/OpenRA.Game/Network/UPnP.cs
@@ -9,7 +9,7 @@
 #endregion
 
 using System;
-
+using System.Net;
 using Mono.Nat;
 
 namespace OpenRA.Network
@@ -116,5 +116,21 @@ namespace OpenRA.Network
 				Game.Settings.Server.AllowPortForward = false;
 			}
 		}
+
+		public static IPAddress GetExternalIP()
+		{
+			if (NatDevice == null)
+				return null;
+
+			try
+			{
+				return NatDevice.GetExternalIP();
+			}
+			catch (Exception e)
+			{
+				Log.Write("server", "Failed to get the external IP from NAT device: {0}", e);
+				return null;
+			}
+		}
 	}
 }
\ No newline at end of file
diff --git a/OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyUtils.cs b/OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyUtils.cs
index cfe9f0ae20..6fa7b03f36 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyUtils.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyUtils.cs
@@ -497,9 +497,9 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 		public static string GetExternalIP(int clientIndex, OrderManager orderManager)
 		{
 			var address = orderManager.LobbyInfo.ClientWithIndex(clientIndex).IpAddress;
-			if (clientIndex == orderManager.LocalClient.Index && address == IPAddress.Loopback.ToString() && UPnP.NatDevice != null)
+			if (clientIndex == orderManager.LocalClient.Index && address == IPAddress.Loopback.ToString())
 			{
-				var externalIP = UPnP.NatDevice.GetExternalIP();
+				var externalIP = UPnP.GetExternalIP();
 				if (externalIP != null)
 					address = externalIP.ToString();
 			}

From b75bfec2f81eec1d47ebfcbeb76b212401af4f5b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Matthias=20Mail=C3=A4nder?= <matthias@mailaender.name>
Date: Mon, 23 Nov 2015 21:40:48 +0100
Subject: [PATCH 2/2] avoid working with NatDevice directly as it is dangerous

---
 OpenRA.Game/Network/UPnP.cs | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/OpenRA.Game/Network/UPnP.cs b/OpenRA.Game/Network/UPnP.cs
index 29525a10f0..af75af65d5 100644
--- a/OpenRA.Game/Network/UPnP.cs
+++ b/OpenRA.Game/Network/UPnP.cs
@@ -16,7 +16,7 @@ namespace OpenRA.Network
 {
 	public static class UPnP
 	{
-		public static INatDevice NatDevice;
+		static INatDevice natDevice;
 
 		public static void TryNatDiscovery()
 		{
@@ -42,7 +42,7 @@ namespace OpenRA.Network
 			Log.Write("server", "Stopping NAT discovery.");
 			NatUtility.StopDiscovery();
 
-			if (NatDevice == null || NatDevice.GetType() != typeof(Mono.Nat.Upnp.UpnpNatDevice))
+			if (natDevice == null || natDevice.GetType() != typeof(Mono.Nat.Upnp.UpnpNatDevice))
 			{
 				Log.Write("server",
 					"No NAT devices with UPnP enabled found within {0} ms deadline. Disabling automatic port forwarding.".F(Game.Settings.Server.NatDiscoveryTimeout));
@@ -60,11 +60,11 @@ namespace OpenRA.Network
 
 			try
 			{
-				NatDevice = args.Device;
-				Log.Write("server", "Type: {0}", NatDevice.GetType());
-				Log.Write("server", "Your external IP is: {0}", NatDevice.GetExternalIP());
+				natDevice = args.Device;
+				Log.Write("server", "Type: {0}", natDevice.GetType());
+				Log.Write("server", "Your external IP is: {0}", natDevice.GetExternalIP());
 
-				foreach (var mp in NatDevice.GetAllMappings())
+				foreach (var mp in natDevice.GetAllMappings())
 					Log.Write("server", "Existing port mapping: protocol={0}, public={1}, private={2}",
 						mp.Protocol, mp.PublicPort, mp.PrivatePort);
 			}
@@ -82,7 +82,7 @@ namespace OpenRA.Network
 			try
 			{
 				var mapping = new Mapping(Protocol.Tcp, Game.Settings.Server.ExternalPort, Game.Settings.Server.ListenPort, lifetime);
-				NatDevice.CreatePortMap(mapping);
+				natDevice.CreatePortMap(mapping);
 				Log.Write("server", "Create port mapping: protocol = {0}, public = {1}, private = {2}, lifetime = {3} s",
 					mapping.Protocol, mapping.PublicPort, mapping.PrivatePort, mapping.Lifetime);
 			}
@@ -106,7 +106,7 @@ namespace OpenRA.Network
 			try
 			{
 				var mapping = new Mapping(Protocol.Tcp, Game.Settings.Server.ExternalPort, Game.Settings.Server.ListenPort);
-				NatDevice.DeletePortMap(mapping);
+				natDevice.DeletePortMap(mapping);
 				Log.Write("server", "Remove port mapping: protocol = {0}, public = {1}, private = {2}, expiration = {3}",
 					mapping.Protocol, mapping.PublicPort, mapping.PrivatePort, mapping.Expiration);
 			}
@@ -119,12 +119,12 @@ namespace OpenRA.Network
 
 		public static IPAddress GetExternalIP()
 		{
-			if (NatDevice == null)
+			if (natDevice == null)
 				return null;
 
 			try
 			{
-				return NatDevice.GetExternalIP();
+				return natDevice.GetExternalIP();
 			}
 			catch (Exception e)
 			{